Merge.
This commit is contained in:
Andreas Gal
commit
d64691a95b
889
pdf.js
889
pdf.js
@ -65,45 +65,46 @@ var Stream = (function() {
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this.dict = dict;
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}
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// required methods for a stream. if a particular stream does not
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// implement these, an error should be thrown
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constructor.prototype = {
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get length() {
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return this.end - this.start;
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},
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getByte: function() {
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var bytes = this.bytes;
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if (this.pos >= this.end)
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return -1;
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return bytes[this.pos++];
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return;
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return this.bytes[this.pos++];
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},
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// returns subarray of original buffer
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// should only be read
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getBytes: function(length) {
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var bytes = this.bytes;
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var pos = this.pos;
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var strEnd = this.end;
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if (!length)
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return bytes.subarray(pos, strEnd);
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var end = pos + length;
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var strEnd = this.end;
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if (!end || end > strEnd)
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if (end > strEnd)
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end = strEnd;
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this.pos = end;
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return bytes.subarray(pos, end);
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},
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lookChar: function() {
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var bytes = this.bytes;
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if (this.pos >= this.end)
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return;
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return String.fromCharCode(bytes[this.pos]);
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return String.fromCharCode(this.bytes[this.pos]);
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},
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getChar: function() {
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var ch = this.lookChar();
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if (!ch)
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return ch;
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this.pos++;
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return ch;
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if (this.pos >= this.end)
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return;
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return String.fromCharCode(this.bytes[this.pos++]);
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},
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skip: function(n) {
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if (!n && !IsNum(n))
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if (!n)
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n = 1;
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this.pos += n;
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},
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@ -135,6 +136,84 @@ var StringStream = (function() {
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return constructor;
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})();
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// super class for the decoding streams
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var DecodeStream = (function() {
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function constructor() {
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this.pos = 0;
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this.bufferLength = 0;
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this.eof = false;
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this.buffer = null;
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}
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constructor.prototype = {
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ensureBuffer: function(requested) {
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var buffer = this.buffer;
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var current = buffer ? buffer.byteLength : 0;
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if (requested < current)
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return buffer;
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var size = 512;
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while (size < requested)
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size <<= 1;
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var buffer2 = Uint8Array(size);
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for (var i = 0; i < current; ++i)
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buffer2[i] = buffer[i];
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return this.buffer = buffer2;
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},
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getByte: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return this.buffer[this.pos++];
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},
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getBytes: function(length) {
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var pos = this.pos;
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this.ensureBuffer(pos + length);
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while (!this.eof && this.bufferLength < pos + length)
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this.readBlock();
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var end = pos + length;
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var bufEnd = this.bufferLength;
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if (end > bufEnd)
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end = bufEnd;
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this.pos = end;
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return this.buffer.subarray(pos, end)
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},
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lookChar: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return String.fromCharCode(this.buffer[this.pos]);
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},
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getChar: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return String.fromCharCode(this.buffer[this.pos++]);
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},
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skip: function(n) {
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if (!n)
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n = 1;
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this.pos += n;
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}
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};
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return constructor;
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})();
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var FlateStream = (function() {
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const codeLenCodeMap = Uint32Array([
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16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
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@ -259,257 +338,195 @@ var FlateStream = (function() {
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this.bytes = bytes;
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this.bytesPos = bytesPos;
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this.eof = false;
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this.codeSize = 0;
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this.codeBuf = 0;
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this.pos = 0;
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this.bufferLength = 0;
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DecodeStream.call(this);
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}
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constructor.prototype = {
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getBits: function(bits) {
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var codeSize = this.codeSize;
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var codeBuf = this.codeBuf;
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var bytes = this.bytes;
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var bytesPos = this.bytesPos;
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constructor.prototype = Object.create(DecodeStream.prototype);
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var b;
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while (codeSize < bits) {
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if (typeof (b = bytes[bytesPos++]) == "undefined")
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error("Bad encoding in flate stream");
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codeBuf |= b << codeSize;
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codeSize += 8;
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}
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b = codeBuf & ((1 << bits) - 1);
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this.codeBuf = codeBuf >> bits;
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this.codeSize = codeSize -= bits;
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this.bytesPos = bytesPos;
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return b;
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},
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getCode: function(table) {
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var codes = table[0];
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var maxLen = table[1];
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var codeSize = this.codeSize;
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var codeBuf = this.codeBuf;
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var bytes = this.bytes;
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var bytesPos = this.bytesPos;
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constructor.prototype.getBits = function(bits) {
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var codeSize = this.codeSize;
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var codeBuf = this.codeBuf;
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var bytes = this.bytes;
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var bytesPos = this.bytesPos;
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while (codeSize < maxLen) {
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var b;
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if (typeof (b = bytes[bytesPos++]) == "undefined")
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error("Bad encoding in flate stream");
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codeBuf |= (b << codeSize);
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codeSize += 8;
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}
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var code = codes[codeBuf & ((1 << maxLen) - 1)];
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var codeLen = code >> 16;
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var codeVal = code & 0xffff;
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if (codeSize == 0|| codeSize < codeLen || codeLen == 0)
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var b;
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while (codeSize < bits) {
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if (typeof (b = bytes[bytesPos++]) == "undefined")
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error("Bad encoding in flate stream");
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this.codeBuf = (codeBuf >> codeLen);
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this.codeSize = (codeSize - codeLen);
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this.bytesPos = bytesPos;
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return codeVal;
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},
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ensureBuffer: function(requested) {
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var buffer = this.buffer;
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var current = buffer ? buffer.length : 0;
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if (requested < current)
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return buffer;
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var size = 512;
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while (size < requested)
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size <<= 1;
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var buffer2 = Uint8Array(size);
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for (var i = 0; i < current; ++i)
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buffer2[i] = buffer[i];
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return this.buffer = buffer2;
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},
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getByte: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return this.buffer[this.pos++];
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},
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getBytes: function(length) {
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var pos = this.pos;
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while (!this.eof && this.bufferLength < pos + length)
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this.readBlock();
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var end = pos + length;
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var bufEnd = this.bufferLength;
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if (end > bufEnd)
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end = bufEnd;
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this.pos = end;
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return this.buffer.subarray(pos, end)
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},
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lookChar: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return String.fromCharCode(this.buffer[pos]);
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},
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getChar: function() {
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var ch = this.lookChar();
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// shouldnt matter what the position is if we get past the eof
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// so no need to check if ch is undefined
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this.pos++;
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return ch;
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},
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skip: function(n) {
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if (!n)
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n = 1;
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this.pos += n;
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},
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generateHuffmanTable: function(lengths) {
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var n = lengths.length;
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// find max code length
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var maxLen = 0;
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for (var i = 0; i < n; ++i) {
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if (lengths[i] > maxLen)
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maxLen = lengths[i];
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}
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// build the table
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var size = 1 << maxLen;
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var codes = Uint32Array(size);
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for (var len = 1, code = 0, skip = 2;
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len <= maxLen;
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++len, code <<= 1, skip <<= 1) {
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for (var val = 0; val < n; ++val) {
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if (lengths[val] == len) {
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// bit-reverse the code
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var code2 = 0;
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var t = code;
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for (var i = 0; i < len; ++i) {
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code2 = (code2 << 1) | (t & 1);
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t >>= 1;
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}
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// fill the table entries
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for (var i = code2; i < size; i += skip)
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codes[i] = (len << 16) | val;
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++code;
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}
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}
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}
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return [codes, maxLen];
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},
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readBlock: function() {
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function repeat(stream, array, len, offset, what) {
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var repeat = stream.getBits(len) + offset;
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while (repeat-- > 0)
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array[i++] = what;
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}
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var bytes = this.bytes;
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var bytesPos = this.bytesPos;
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// read block header
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var hdr = this.getBits(3);
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if (hdr & 1)
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this.eof = true;
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hdr >>= 1;
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codeBuf |= b << codeSize;
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codeSize += 8;
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}
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b = codeBuf & ((1 << bits) - 1);
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this.codeBuf = codeBuf >> bits;
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this.codeSize = codeSize -= bits;
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this.bytesPos = bytesPos;
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return b;
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};
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constructor.prototype.getCode = function(table) {
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var codes = table[0];
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var maxLen = table[1];
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var codeSize = this.codeSize;
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var codeBuf = this.codeBuf;
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var bytes = this.bytes;
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var bytesPos = this.bytesPos;
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while (codeSize < maxLen) {
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var b;
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if (hdr == 0) { // uncompressed block
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if (typeof (b = bytes[bytesPos++]) == "undefined")
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error("Bad block header in flate stream");
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var blockLen = b;
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if (typeof (b = bytes[bytesPos++]) == "undefined")
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error("Bad block header in flate stream");
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blockLen |= (b << 8);
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if (typeof (b = bytes[bytesPos++]) == "undefined")
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error("Bad block header in flate stream");
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var check = b;
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if (typeof (b = bytes[bytesPos++]) == "undefined")
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error("Bad block header in flate stream");
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check |= (b << 8);
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if (check != (~this.blockLen & 0xffff))
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error("Bad uncompressed block length in flate stream");
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var bufferLength = this.bufferLength;
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var buffer = this.ensureBuffer(bufferLength + blockLen);
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this.bufferLength = bufferLength + blockLen;
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for (var n = bufferLength; n < blockLen; ++n) {
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if (typeof (b = bytes[bytesPos++]) == "undefined") {
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this.eof = true;
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break;
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if (typeof (b = bytes[bytesPos++]) == "undefined")
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error("Bad encoding in flate stream");
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codeBuf |= (b << codeSize);
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codeSize += 8;
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}
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var code = codes[codeBuf & ((1 << maxLen) - 1)];
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var codeLen = code >> 16;
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var codeVal = code & 0xffff;
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if (codeSize == 0|| codeSize < codeLen || codeLen == 0)
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error("Bad encoding in flate stream");
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this.codeBuf = (codeBuf >> codeLen);
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this.codeSize = (codeSize - codeLen);
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this.bytesPos = bytesPos;
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return codeVal;
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};
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constructor.prototype.generateHuffmanTable = function(lengths) {
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var n = lengths.length;
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// find max code length
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var maxLen = 0;
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for (var i = 0; i < n; ++i) {
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if (lengths[i] > maxLen)
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maxLen = lengths[i];
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}
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// build the table
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var size = 1 << maxLen;
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var codes = Uint32Array(size);
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for (var len = 1, code = 0, skip = 2;
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len <= maxLen;
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++len, code <<= 1, skip <<= 1) {
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for (var val = 0; val < n; ++val) {
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if (lengths[val] == len) {
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// bit-reverse the code
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var code2 = 0;
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var t = code;
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for (var i = 0; i < len; ++i) {
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code2 = (code2 << 1) | (t & 1);
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t >>= 1;
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}
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buffer[n] = b;
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// fill the table entries
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for (var i = code2; i < size; i += skip)
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codes[i] = (len << 16) | val;
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++code;
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}
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}
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}
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return [codes, maxLen];
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};
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constructor.prototype.readBlock = function() {
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function repeat(stream, array, len, offset, what) {
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var repeat = stream.getBits(len) + offset;
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while (repeat-- > 0)
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array[i++] = what;
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}
|
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var bytes = this.bytes;
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var bytesPos = this.bytesPos;
|
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|
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// read block header
|
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var hdr = this.getBits(3);
|
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if (hdr & 1)
|
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this.eof = true;
|
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hdr >>= 1;
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|
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var b;
|
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if (hdr == 0) { // uncompressed block
|
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if (typeof (b = bytes[bytesPos++]) == "undefined")
|
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error("Bad block header in flate stream");
|
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var blockLen = b;
|
||||
if (typeof (b = bytes[bytesPos++]) == "undefined")
|
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error("Bad block header in flate stream");
|
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blockLen |= (b << 8);
|
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if (typeof (b = bytes[bytesPos++]) == "undefined")
|
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error("Bad block header in flate stream");
|
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var check = b;
|
||||
if (typeof (b = bytes[bytesPos++]) == "undefined")
|
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error("Bad block header in flate stream");
|
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check |= (b << 8);
|
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if (check != (~this.blockLen & 0xffff))
|
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error("Bad uncompressed block length in flate stream");
|
||||
var bufferLength = this.bufferLength;
|
||||
var buffer = this.ensureBuffer(bufferLength + blockLen);
|
||||
this.bufferLength = bufferLength + blockLen;
|
||||
for (var n = bufferLength; n < blockLen; ++n) {
|
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if (typeof (b = bytes[bytesPos++]) == "undefined") {
|
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this.eof = true;
|
||||
break;
|
||||
}
|
||||
buffer[n] = b;
|
||||
}
|
||||
return;
|
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}
|
||||
|
||||
var litCodeTable;
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var distCodeTable;
|
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if (hdr == 1) { // compressed block, fixed codes
|
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litCodeTable = fixedLitCodeTab;
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distCodeTable = fixedDistCodeTab;
|
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} else if (hdr == 2) { // compressed block, dynamic codes
|
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var numLitCodes = this.getBits(5) + 257;
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var numDistCodes = this.getBits(5) + 1;
|
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var numCodeLenCodes = this.getBits(4) + 4;
|
||||
|
||||
// build the code lengths code table
|
||||
var codeLenCodeLengths = Array(codeLenCodeMap.length);
|
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var i = 0;
|
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while (i < numCodeLenCodes)
|
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codeLenCodeLengths[codeLenCodeMap[i++]] = this.getBits(3);
|
||||
var codeLenCodeTab = this.generateHuffmanTable(codeLenCodeLengths);
|
||||
|
||||
// build the literal and distance code tables
|
||||
var len = 0;
|
||||
var i = 0;
|
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var codes = numLitCodes + numDistCodes;
|
||||
var codeLengths = new Array(codes);
|
||||
while (i < codes) {
|
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var code = this.getCode(codeLenCodeTab);
|
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if (code == 16) {
|
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repeat(this, codeLengths, 2, 3, len);
|
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} else if (code == 17) {
|
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repeat(this, codeLengths, 3, 3, len = 0);
|
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} else if (code == 18) {
|
||||
repeat(this, codeLengths, 7, 11, len = 0);
|
||||
} else {
|
||||
codeLengths[i++] = len = code;
|
||||
}
|
||||
}
|
||||
|
||||
litCodeTable =
|
||||
this.generateHuffmanTable(codeLengths.slice(0, numLitCodes));
|
||||
distCodeTable =
|
||||
this.generateHuffmanTable(codeLengths.slice(numLitCodes, codes));
|
||||
} else {
|
||||
error("Unknown block type in flate stream");
|
||||
}
|
||||
|
||||
var pos = this.bufferLength;
|
||||
while (true) {
|
||||
var code1 = this.getCode(litCodeTable);
|
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if (code1 == 256) {
|
||||
this.bufferLength = pos;
|
||||
return;
|
||||
}
|
||||
|
||||
var litCodeTable;
|
||||
var distCodeTable;
|
||||
if (hdr == 1) { // compressed block, fixed codes
|
||||
litCodeTable = fixedLitCodeTab;
|
||||
distCodeTable = fixedDistCodeTab;
|
||||
} else if (hdr == 2) { // compressed block, dynamic codes
|
||||
var numLitCodes = this.getBits(5) + 257;
|
||||
var numDistCodes = this.getBits(5) + 1;
|
||||
var numCodeLenCodes = this.getBits(4) + 4;
|
||||
|
||||
// build the code lengths code table
|
||||
var codeLenCodeLengths = Array(codeLenCodeMap.length);
|
||||
var i = 0;
|
||||
while (i < numCodeLenCodes)
|
||||
codeLenCodeLengths[codeLenCodeMap[i++]] = this.getBits(3);
|
||||
var codeLenCodeTab = this.generateHuffmanTable(codeLenCodeLengths);
|
||||
|
||||
// build the literal and distance code tables
|
||||
var len = 0;
|
||||
var i = 0;
|
||||
var codes = numLitCodes + numDistCodes;
|
||||
var codeLengths = new Array(codes);
|
||||
while (i < codes) {
|
||||
var code = this.getCode(codeLenCodeTab);
|
||||
if (code == 16) {
|
||||
repeat(this, codeLengths, 2, 3, len);
|
||||
} else if (code == 17) {
|
||||
repeat(this, codeLengths, 3, 3, len = 0);
|
||||
} else if (code == 18) {
|
||||
repeat(this, codeLengths, 7, 11, len = 0);
|
||||
} else {
|
||||
codeLengths[i++] = len = code;
|
||||
}
|
||||
}
|
||||
|
||||
litCodeTable = this.generateHuffmanTable(codeLengths.slice(0, numLitCodes));
|
||||
distCodeTable = this.generateHuffmanTable(codeLengths.slice(numLitCodes, codes));
|
||||
if (code1 < 256) {
|
||||
var buffer = this.ensureBuffer(pos + 1);
|
||||
buffer[pos++] = code1;
|
||||
} else {
|
||||
error("Unknown block type in flate stream");
|
||||
}
|
||||
|
||||
var pos = this.bufferLength;
|
||||
var buffer = this.buffer;
|
||||
var limit = buffer ? buffer.length : 0;
|
||||
while (true) {
|
||||
var code1 = this.getCode(litCodeTable);
|
||||
if (code1 < 256) {
|
||||
if (pos + 1 >= limit) {
|
||||
buffer = this.ensureBuffer(pos + 1);
|
||||
limit = buffer.length;
|
||||
}
|
||||
buffer[pos++] = code1;
|
||||
continue;
|
||||
}
|
||||
if (code1 == 256) {
|
||||
this.bufferLength = pos;
|
||||
return;
|
||||
}
|
||||
code1 -= 257;
|
||||
code1 = lengthDecode[code1];
|
||||
var code2 = code1 >> 16;
|
||||
@ -522,10 +539,7 @@ var FlateStream = (function() {
|
||||
if (code2 > 0)
|
||||
code2 = this.getBits(code2);
|
||||
var dist = (code1 & 0xffff) + code2;
|
||||
if (pos + len >= limit) {
|
||||
buffer = this.ensureBuffer(pos + len);
|
||||
limit = buffer.length;
|
||||
}
|
||||
var buffer = this.ensureBuffer(pos + len);
|
||||
for (var k = 0; k < len; ++k, ++pos)
|
||||
buffer[pos] = buffer[pos - dist];
|
||||
}
|
||||
@ -534,6 +548,183 @@ var FlateStream = (function() {
|
||||
|
||||
return constructor;
|
||||
})();
|
||||
|
||||
var PredictorStream = (function() {
|
||||
function constructor(stream, params) {
|
||||
var predictor = this.predictor = params.get("Predictor") || 1;
|
||||
|
||||
if (predictor <= 1)
|
||||
return stream; // no prediction
|
||||
if (predictor !== 2 && (predictor < 10 || predictor > 15))
|
||||
error("Unsupported predictor");
|
||||
|
||||
if (predictor === 2)
|
||||
this.readBlock = this.readBlockTiff;
|
||||
else
|
||||
this.readBlock = this.readBlockPng;
|
||||
|
||||
this.stream = stream;
|
||||
this.dict = stream.dict;
|
||||
if (params.has("EarlyChange")) {
|
||||
error("EarlyChange predictor parameter is not supported");
|
||||
}
|
||||
var colors = this.colors = params.get("Colors") || 1;
|
||||
var bits = this.bits = params.get("BitsPerComponent") || 8;
|
||||
var columns = this.columns = params.get("Columns") || 1;
|
||||
|
||||
var pixBytes = this.pixBytes = (colors * bits + 7) >> 3;
|
||||
// add an extra pixByte to represent the pixel left of column 0
|
||||
var rowBytes = this.rowBytes = (columns * colors * bits + 7) >> 3;
|
||||
|
||||
DecodeStream.call(this);
|
||||
}
|
||||
|
||||
constructor.prototype = Object.create(DecodeStream.prototype);
|
||||
|
||||
constructor.prototype.readBlockTiff = function() {
|
||||
var buffer = this.buffer;
|
||||
var pos = this.pos;
|
||||
|
||||
var rowBytes = this.rowBytes;
|
||||
var pixBytes = this.pixBytes;
|
||||
|
||||
|
||||
var buffer = this.buffer;
|
||||
var bufferLength = this.bufferLength;
|
||||
this.ensureBuffer(bufferLength + rowBytes);
|
||||
var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
|
||||
|
||||
var bits = this.bits;
|
||||
var colors = this.colors;
|
||||
|
||||
var rawBytes = this.stream.getBytes(rowBytes);
|
||||
|
||||
if (bits === 1) {
|
||||
var inbuf = 0;
|
||||
for (var i = 0; i < rowBytes; ++i) {
|
||||
var c = rawBytes[i];
|
||||
inBuf = (inBuf << 8) | c;
|
||||
// bitwise addition is exclusive or
|
||||
// first shift inBuf and then add
|
||||
currentRow[i] = (c ^ (inBuf >> colors)) & 0xFF;
|
||||
// truncate inBuf (assumes colors < 16)
|
||||
inBuf &= 0xFFFF;
|
||||
}
|
||||
} else if (bits === 8) {
|
||||
for (var i = 0; i < colors; ++i)
|
||||
currentRow[i] = rawBytes[i];
|
||||
for (; i < rowBytes; ++i)
|
||||
currentRow[i] = currentRow[i - colors] + rawBytes[i];
|
||||
} else {
|
||||
var compArray = new Uint8Array(colors + 1);
|
||||
var bitMask = (1 << bits) - 1;
|
||||
var inbuf = 0, outbut = 0;
|
||||
var inbits = 0, outbits = 0;
|
||||
var j = 0, k = 0;
|
||||
var columns = this.columns;
|
||||
for (var i = 0; i < columns; ++i) {
|
||||
for (var kk = 0; kk < colors; ++kk) {
|
||||
if (inbits < bits) {
|
||||
inbuf = (inbuf << 8) | (rawBytes[j++] & 0xFF);
|
||||
inbits += 8;
|
||||
}
|
||||
compArray[kk] = (compArray[kk] +
|
||||
(inbuf >> (inbits - bits))) & bitMask;
|
||||
inbits -= bits;
|
||||
outbuf = (outbuf << bits) | compArray[kk];
|
||||
outbits += bits;
|
||||
if (outbits >= 8) {
|
||||
currentRow[k++] = (outbuf >> (outbits - 8)) & 0xFF;
|
||||
outbits -= 8;
|
||||
}
|
||||
}
|
||||
}
|
||||
if (outbits > 0) {
|
||||
currentRow[k++] = (outbuf << (8 - outbits)) +
|
||||
(inbuf & ((1 << (8 - outbits)) - 1))
|
||||
}
|
||||
}
|
||||
this.bufferLength += rowBytes;
|
||||
};
|
||||
constructor.prototype.readBlockPng = function() {
|
||||
var buffer = this.buffer;
|
||||
var pos = this.pos;
|
||||
|
||||
var rowBytes = this.rowBytes;
|
||||
var pixBytes = this.pixBytes;
|
||||
|
||||
var predictor = this.stream.getByte();
|
||||
var rawBytes = this.stream.getBytes(rowBytes);
|
||||
|
||||
var buffer = this.buffer;
|
||||
var bufferLength = this.bufferLength;
|
||||
this.ensureBuffer(bufferLength + pixBytes);
|
||||
|
||||
var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
|
||||
var prevRow = buffer.subarray(bufferLength - rowBytes, bufferLength);
|
||||
if (prevRow.length == 0)
|
||||
prevRow = currentRow;
|
||||
|
||||
switch (predictor) {
|
||||
case 0:
|
||||
break;
|
||||
case 1:
|
||||
for (var i = 0; i < pixBytes; ++i)
|
||||
currentRow[i] = rawBytes[i];
|
||||
for (; i < rowBytes; ++i)
|
||||
currentRow[i] = (currentRow[i - pixBytes] + rawBytes[i]) & 0xFF;
|
||||
break;
|
||||
case 2:
|
||||
for (var i = 0; i < rowBytes; ++i)
|
||||
currentRow[i] = (prevRow[i] + rawBytes[i]) & 0xFF;
|
||||
break;
|
||||
case 3:
|
||||
for (var i = 0; i < pixBytes; ++i)
|
||||
currentRow[i] = (prevRow[i] >> 1) + rawBytes[i];
|
||||
for (; i < rowBytes; ++i)
|
||||
currentRow[i] = (((prevRow[i] + currentRow[i - pixBytes])
|
||||
>> 1) + rawBytes[i]) & 0xFF;
|
||||
break;
|
||||
case 4:
|
||||
// we need to save the up left pixels values. the simplest way
|
||||
// is to create a new buffer
|
||||
for (var i = 0; i < pixBytes; ++i)
|
||||
currentRow[i] = rawBytes[i];
|
||||
for (; i < rowBytes; ++i) {
|
||||
var up = prevRow[i];
|
||||
var upLeft = lastRow[i - pixBytes];
|
||||
var left = currentRow[i - pixBytes];
|
||||
var p = left + up - upLeft;
|
||||
|
||||
var pa = p - left;
|
||||
if (pa < 0)
|
||||
pa = -pa;
|
||||
var pb = p - up;
|
||||
if (pb < 0)
|
||||
pb = -pb;
|
||||
var pc = p - upLeft;
|
||||
if (pc < 0)
|
||||
pc = -pc;
|
||||
|
||||
var c = rawBytes[i];
|
||||
if (pa <= pb && pa <= pc)
|
||||
currentRow[i] = left + c;
|
||||
else if (pb <= pc)
|
||||
currentRow[i] = up + c;
|
||||
else
|
||||
currentRow[i] = upLeft + c;
|
||||
break;
|
||||
}
|
||||
default:
|
||||
error("Unsupported predictor");
|
||||
break;
|
||||
}
|
||||
this.bufferLength += rowBytes;
|
||||
};
|
||||
|
||||
return constructor;
|
||||
})();
|
||||
|
||||
// A JpegStream can't be read directly. We use the platform to render the underlying
|
||||
// JPEG data for us.
|
||||
var JpegStream = (function() {
|
||||
@ -558,196 +749,6 @@ var JpegStream = (function() {
|
||||
|
||||
return constructor;
|
||||
})();
|
||||
|
||||
var PredictorStream = (function() {
|
||||
function constructor(stream, params) {
|
||||
var predictor = this.predictor = params.get("Predictor") || 1;
|
||||
|
||||
if (predictor <= 1)
|
||||
return stream; // no prediction
|
||||
if (predictor !== 2 && (predictor < 10 || predictor > 15))
|
||||
error("Unsupported predictor");
|
||||
|
||||
if (predictor === 2)
|
||||
this.readRow = this.readRowTiff;
|
||||
else
|
||||
this.readRow = this.readRowPng;
|
||||
|
||||
this.stream = stream;
|
||||
this.dict = stream.dict;
|
||||
if (params.has("EarlyChange")) {
|
||||
error("EarlyChange predictor parameter is not supported");
|
||||
}
|
||||
var colors = this.colors = params.get("Colors") || 1;
|
||||
var bits = this.bits = params.get("BitsPerComponent") || 8;
|
||||
var columns = this.columns = params.get("Columns") || 1;
|
||||
|
||||
var pixBytes = this.pixBytes = (colors * bits + 7) >> 3;
|
||||
// add an extra pixByte to represent the pixel left of column 0
|
||||
var rowBytes = this.rowBytes = ((columns * colors * bits + 7) >> 3) + pixBytes;
|
||||
|
||||
this.currentRow = new Uint8Array(rowBytes);
|
||||
this.bufferLength = rowBytes;
|
||||
this.pos = rowBytes;
|
||||
}
|
||||
|
||||
constructor.prototype = {
|
||||
readRowTiff : function() {
|
||||
var currentRow = this.currentRow;
|
||||
var rowBytes = this.rowBytes;
|
||||
var pixBytes = this.pixBytes;
|
||||
var bits = this.bits;
|
||||
var colors = this.colors;
|
||||
|
||||
var rawBytes = this.stream.getBytes(rowBytes - pixBytes);
|
||||
|
||||
if (bits === 1) {
|
||||
var inbuf = 0;
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j) {
|
||||
var c = rawBytes[j];
|
||||
inBuf = (inBuf << 8) | c;
|
||||
// bitwise addition is exclusive or
|
||||
// first shift inBuf and then add
|
||||
currentRow[i] = (c ^ (inBuf >> colors)) & 0xFF;
|
||||
// truncate inBuf (assumes colors < 16)
|
||||
inBuf &= 0xFFFF;
|
||||
}
|
||||
} else if (bits === 8) {
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j)
|
||||
currentRow[i] = currentRow[i - colors] + rawBytes[j];
|
||||
} else {
|
||||
var compArray = new Uint8Array(colors + 1);
|
||||
var bitMask = (1 << bits) - 1;
|
||||
var inbuf = 0, outbut = 0;
|
||||
var inbits = 0, outbits = 0;
|
||||
var j = 0, k = pixBytes;
|
||||
var columns = this.columns;
|
||||
for (var i = 0; i < columns; ++i) {
|
||||
for (var kk = 0; kk < colors; ++kk) {
|
||||
if (inbits < bits) {
|
||||
inbuf = (inbuf << 8) | (rawBytes[j++] & 0xFF);
|
||||
inbits += 8;
|
||||
}
|
||||
compArray[kk] = (compArray[kk] +
|
||||
(inbuf >> (inbits - bits))) & bitMask;
|
||||
inbits -= bits;
|
||||
outbuf = (outbuf << bits) | compArray[kk];
|
||||
outbits += bits;
|
||||
if (outbits >= 8) {
|
||||
currentRow[k++] = (outbuf >> (outbits - 8)) & 0xFF;
|
||||
outbits -= 8;
|
||||
}
|
||||
}
|
||||
}
|
||||
if (outbits > 0) {
|
||||
currentRow[k++] = (outbuf << (8 - outbits)) +
|
||||
(inbuf & ((1 << (8 - outbits)) - 1))
|
||||
}
|
||||
}
|
||||
this.pos = pixBytes;
|
||||
},
|
||||
readRowPng : function() {
|
||||
var currentRow = this.currentRow;
|
||||
|
||||
var rowBytes = this.rowBytes;
|
||||
var pixBytes = this.pixBytes;
|
||||
|
||||
var predictor = this.stream.getByte();
|
||||
var rawBytes = this.stream.getBytes(rowBytes - pixBytes);
|
||||
|
||||
switch (predictor) {
|
||||
case 0:
|
||||
break;
|
||||
case 1:
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j)
|
||||
currentRow[i] = (currentRow[i - pixBytes] + rawBytes[j]) & 0xFF;
|
||||
break;
|
||||
case 2:
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j)
|
||||
currentRow[i] = (currentRow[i] + rawBytes[j]) & 0xFF;
|
||||
break;
|
||||
case 3:
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j)
|
||||
currentRow[i] = (((currentRow[i] + currentRow[i - pixBytes])
|
||||
>> 1) + rawBytes[j]) & 0xFF;
|
||||
break;
|
||||
case 4:
|
||||
// we need to save the up left pixels values. the simplest way
|
||||
// is to create a new buffer
|
||||
var lastRow = currentRow;
|
||||
var currentRow = new Uint8Array(rowBytes);
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j) {
|
||||
var up = lastRow[i];
|
||||
var upLeft = lastRow[i - pixBytes];
|
||||
var left = currentRow[i - pixBytes];
|
||||
var p = left + up - upLeft;
|
||||
|
||||
var pa = p - left;
|
||||
if (pa < 0)
|
||||
pa = -pa;
|
||||
var pb = p - up;
|
||||
if (pb < 0)
|
||||
pb = -pb;
|
||||
var pc = p - upLeft;
|
||||
if (pc < 0)
|
||||
pc = -pc;
|
||||
|
||||
var c = rawBytes[j];
|
||||
if (pa <= pb && pa <= pc)
|
||||
currentRow[i] = left + c;
|
||||
else if (pb <= pc)
|
||||
currentRow[i] = up + c;
|
||||
else
|
||||
currentRow[i] = upLeft + c;
|
||||
break;
|
||||
this.currentRow = currentRow;
|
||||
}
|
||||
default:
|
||||
error("Unsupported predictor");
|
||||
break;
|
||||
}
|
||||
this.pos = pixBytes;
|
||||
},
|
||||
getByte : function() {
|
||||
if (this.pos >= this.bufferLength)
|
||||
this.readRow();
|
||||
return this.currentRow[this.pos++];
|
||||
},
|
||||
getBytes : function(n) {
|
||||
var i, bytes;
|
||||
bytes = new Uint8Array(n);
|
||||
for (i = 0; i < n; ++i) {
|
||||
if (this.pos >= this.bufferLength)
|
||||
this.readRow();
|
||||
bytes[i] = this.currentRow[this.pos++];
|
||||
}
|
||||
return bytes;
|
||||
},
|
||||
getChar : function() {
|
||||
return String.formCharCode(this.getByte());
|
||||
},
|
||||
lookChar : function() {
|
||||
if (this.pos >= this.bufferLength)
|
||||
this.readRow();
|
||||
return String.formCharCode(this.currentRow[this.pos]);
|
||||
},
|
||||
skip : function(n) {
|
||||
var i;
|
||||
if (!n) {
|
||||
n = 1;
|
||||
}
|
||||
while (n > this.bufferLength - this.pos) {
|
||||
n -= this.bufferLength - this.pos;
|
||||
this.readRow();
|
||||
if (this.bufferLength === 0) break;
|
||||
}
|
||||
this.pos += n;
|
||||
}
|
||||
};
|
||||
|
||||
return constructor;
|
||||
})();
|
||||
|
||||
var DecryptStream = (function() {
|
||||
function constructor(str, fileKey, encAlgorithm, keyLength) {
|
||||
TODO("decrypt stream is not implemented");
|
||||
|
||||
Loading…
Reference in New Issue
Block a user